Add support for threads count

[simonepri]

Example:

❯ ps M -p 2100        
USER        PID   TT   %CPU STAT PRI     STIME     UTIME COMMAND
simonepri  2100   ??    1.9 R    47T   0:01.72   0:18.31 /Applications/Utilities/Terminal.app/Contents/MacOS/Terminal
           2100         0.0 S    20T   0:00.00   0:00.00 
           2100         0.0 S    31T   0:00.00   0:00.00 
           2100         0.0 S    31T   0:00.54   0:00.33 
           2100         0.0 S    47T   0:00.92   0:00.56 
           2100         0.1 S    61T   0:00.00   0:00.03 
           2100         0.1 S    47T   0:00.00   0:00.02 
           2100         0.0 S    61T   0:00.00   0:00.01 
           2100         0.1 S    47T   0:00.00   0:00.01 

To count them:

❯ ps M -p 2100 | wc -l
      10

@soyuka any idea on how can we support this?

[simonepri]

wmic has the ThreadCount column so it's quite easy to add it on Windows.

[simonepri]

ps on AIX has the thcount column.
https://superuser.com/a/49411/470946

[simonepri]

proc files have the Thread value
http://ask.xmodulo.com/number-of-threads-process-linux.html

[soyuka]

Nice research! I agree this could be a nice addition!

[simonepri]

Can't find a nice way to do it with ps, though.

[soyuka]

thcount seems available on linux

[simonepri]

Cool so the problem is only macOS :(

[soyuka]

Yes :| https://stackoverflow.com/questions/28047653/osx-how-can-i-see-the-tid-of-all-threads-from-my-process

[soyuka]

I guess we could introduce this and set a default number for os x while we find a way to do this properly on os x.

[simonepri]

On macOS we need a custom ps command and a custom parsing function.
I'll try to work on it as soon as my exam session ends.

[soyuka]

Maybe we need to dig deeper into how the Activity Monitor does the thread count also.

Sure dude, there's no rush in open source software :D. Good luck with your exams!

[simonepri]

Just for reference, thats how multi threaded process are reported by ps.

[soyuka]

that's cool!

Could you check on os x if you have:
/proc/{pid}/tasks (number of files, maybe faster then reading status) or /proc/{pid}/status (search the file for Threads) ?

[simonepri]

On macOS there's no /proc folder sadly.
I'll take a look on how cpuUsage() works under the hood in node, for sure there's some particular syscall to call to obtain the same info.

[soyuka]

Not sure that they actually use the number of threads :|. We won't be able to make this work without bindings.

[hiyelbaz]

Would you consider adding this feature for Linux and Windows only? Related function can return -1 on macOS which would indicate that the platform is not supported.